Trying To Save A Lovely Classic From The Scrapyard

[fuddymucker]

I wish you lived nearer too STEVE2006, then I could remove each of your components 1 by 1 until mine worked, then I could be sure what was wrong :winky:

[fuddymucker]

Last night I removed and checked the sparkplugs, HT leads, dissy caps, rotor arms, cambelt timing and while the plugs were out I also did a compression test and was amazed to find all 8 cylinders above 210 psi, that was such a relief to know the engine is ok and it is just the control that’s faulty.

Just out of curiosity does anyone know the original factory psi pressures?

[fuddymucker]

Well time is up for this old bus, I have tried so much with no glimmer of sucess

HT LEADS

DISSY CAPS

ROTOR ARMS

PLUGS

COMPRESSION

OHM TESTS ON CAM AND CRANK SENSORS

IGNITORS

COILS

TODAY I EVEN REMOVED THE TIMING BELT, PULLYS ECT AND REBUILT HER

She is not running any better, still wont go above 2000rmp, still running very rich, if you try to get her above 2000rpm her cats glow cherry red and still shows no error codes.

I am now tired and thinking enough is enough.

Thanks for you help anyway it was worth a shot, now I'm gonna get shot.

[steve2006]

Hi,

Sorry we haven't been able to get you going,you seem to have covered all the possibles,if you are getting rid please give me 1st option

[SteveLS400]

What about the air filter and assembly? Throttle body? Appreciate you must be very frustrated

[fuddymucker]

What about the air filter and assembly? Throttle body? Appreciate you must be very frustrated

Yes the air filer and assembly is ok, the throttle body and top intake I removed a couple days ago and cleaned up by hand (the throttle body was really dirty on the back side, maybe because it has been running so rich on Limp Home Mode).

Thanks for the sudjestion, and yes I am fast running out of love for it.

Just wish I could park next to another LS400 and start swaping parts with known good units like ECU, MAP ect..

[JellyBean]

What about the air filter and assembly? Throttle body? Appreciate you must be very frustrated

Yes the air filer and assembly is ok, the throttle body and top intake I removed a couple days ago and cleaned up by hand (the throttle body was really dirty on the back side, maybe because it has been running so rich on Limp Home Mode).

Thanks for the sudjestion, and yes I am fast running out of love for it.

Just wish I could park next to another LS400 and start swaping parts with known good units like ECU, MAP ect..

Don't give up. Have two or three days without touching it until you feel mentally stronger again. I am deadly serious - I have been there with other cars and many other malfunctioning things. (I could write a small book about my central heating woes.) Somebody will come up with the answer and since the engine itself is sound, it is likely something relatively simple. Have a rest. And when it is fixed, you will be DELIGHTED you stuck with it. I guarantee this.

[Malc]

Just a thought !

Have you actually asked BENFUR on here if he can possibly diagnose ....... bearing in mind all that you have done thus far.

Then, if that fails to resolve the issue maybe it's worth considering getting a Lexus LS specialist or Dealer to diagnose for you.

It might be something really simple and if it's the ECU or summat expensive then Benfur will probably be able to supply something usefully economic to rectify.

Malc

[ROYT]

This is a quote from the w/s manual.

Diag code 21,28: MAIN OXYGEN SENSOR CIRCUIT

The main oxygen sensor senses whether the air fuel ratio is richer or

leaner than the stoichiometric air-fuel ratio.

Aftr more technical info on its constuction, the crux is that the sensor generates a voltage

signal sent to the ECU which uses this signal to increase or reduce the injection volume

to keep the air fuel ratio at an even value near the stoichiometric air fuel ratio.

The main oxygen sensors include a heater which heats the element.this heater is

controlled by the ECU.

code 21 is left bank, 28 is right bank.

Don't know if this is relevant.......there is also the cold start injector is it turning off?

and the fuel line pressure...

Stick at it, you will be an expert and we can all call on you!

[benfur]

Just a thought !

Have you actually asked BENFUR on here if he can possibly diagnose ....... bearing in mind all that you have done thus far.

Then, if that fails to resolve the issue maybe it's worth considering getting a Lexus LS specialist or Dealer to diagnose for you.

It might be something really simple and if it's the ECU or summat expensive then Benfur will probably be able to supply something usefully economic to rectify.

Malc

Hi

I have watched your posting with interest

unfortunately , you and the guys on here have covered most points

I don't think its the crank sensor - as its failure normally results in no spark

Even though you have cleaned the Throttle body - it still may have a blockage, and tends not to respond well to dismantling and re assembly

Plus the TPS sensors may be faulty

The Airflow meter is my guess or the complete Throttle Body with TPS sensors still attached.

The Engine Ecu have been known to play up , and it is known that some had a bug in them causing running issues including intermittent cutting out.

Sorry cant be of more help

Maurice

[Steve ( West Mids )]

Surely next move is to pay Lexus to do a diagnostics?

[fuddymucker]

The problem I have is that I paid £500 for the car plus getting it home and endless hours trying to fix it that now I beleive I could have got a working one from eBay for that sort of money.

If I spend much more on it without any luck then I will only get my money back by breaking her myself.

The other problem (that I don't understand because she has caused me so much frustration in just 1 week) is that I do like the old dog and don't want to rip her up bit by bit to post body parts around the country.

Does anyone on this forum live in Somerset who can help me out testing parts for known good parts?

Cheers

[fuddymucker]

Ok I am back again and after a wiring diagram that shows the cam sensor wirings.

The reason for this is although the sensors meter out fine from the sensors connector plugs, they dont mesuring back down the loom from the other half of the sensor plug.

The left cam sensor measures 10 ohms where the right measures over 110 ohms, need to follow them on a wiring diagram to check them point to point.

I am only guessing now but if the ohms are to high the sensor wont be sending back a signal to the ecu, if the ecu gets no signal it thinks that cam aint moving.

Clasping at straws maybe?

[Manc]

Alright Mucker?

Don't give up mate, I've kept my '93plate on the road with the help of people here & lexls.com. You need to diagnose the faults here before lexls.com.

I too have that orange engine light on... with mine its to do with the EGR pipe (exhaust gas re-circulation or something..) its cracked and fails the MOT due to high emissions.

You should hear a slight blowing sound when parked in confined spaces, or just open bonnet and put head near windscreen and the pipe is directly in the middle down the back (between engine block & bulkhead)

This brought me 3 error codes (13, 25 & 31) The explainations for these codes have several answers and are not clear to the amatuer user like myself but looking at all 3, it's something to do with air....

Mines due another MOT soon and i should be replacing the pipe, so i'll let you know if I can clear the warnings after replacement....

I too read all the info on sensors here & there, i also read about a bloke who had replaced all these at hundres of pounds and was still having difficulties.... so check the EGR pipe before any replacements...

The 2000revs could be just the Throttlebody intake jets blocked...(fairly easy job). My car suddenly started to chugg & fail to go when accelerating. It started as a few shudders when needing more gas, but eventually it got worse and my car stopped in the main road after pulling out of a side street. The engine was still running but had zero power. Very embarrasing, but made me fix it.

Took me 2 hours with cups of tea and double checking, so is an easy job that needs basic tools and some good cleaning fluid (see lexls.com).

The engine should be ok, mine hasnt had a proper service in 5 years and is still going strong. I do fully intend to give her a proper service asap... you can't ride your luck that long with cars... but it does show what a reliable engine this is.

Other main costs will include:-

the control arms (all round, 4 front, 2 rear),

a flickering dash (although this could explain your 60k on the clock... a new dash can wipe previous miles) - an LS at 60k isn't even worn in yet!!!

A proper Lexus service.....

smaller costs include:-

replacing brake pipes (not brakelines, the steel pipes these attach to that carry the fluid around the car...)

exhaust gaskets (2 near the cats @ the front)

bonnet struts

a/c display

flickering dash

There are others but its all i can remember for now

Good luck & it should be alright mate

(edit**) sorry, i only read page one before posting this.... but code 21 says its the "Main O2s & Heater signal, and 28 is the Main O2s.

so it looks like you are on the right path..you now just need that path lighting up eh?

[JellyBean]

Other main costs will include:-

the control arms (all round, 4 front, 2 rear),

a flickering dash (although this could explain your 60k on the clock... a new dash can wipe previous miles) - an LS at 60k isn't even worn in yet!!!

A proper Lexus service.....

smaller costs include:-

replacing brake pipes (not brakelines, the steel pipes these attach to that carry the fluid around the car...)

exhaust gaskets (2 near the cats @ the front)

bonnet struts

a/c display

flickering dash

Driver's seat heater!

[Manc]

Other main costs will include:-

the control arms (all round, 4 front, 2 rear),

a flickering dash (although this could explain your 60k on the clock... a new dash can wipe previous miles) - an LS at 60k isn't even worn in yet!!!

A proper Lexus service.....

smaller costs include:-

replacing brake pipes (not brakelines, the steel pipes these attach to that carry the fluid around the car...)

exhaust gaskets (2 near the cats @ the front)

bonnet struts

a/c display

flickering dash

Driver's seat heater!

Mines still working fine... but i cant work my front window, and the front passenger side only oopens by my control, not the passengers..... but hey, small stuff really

[fuddymucker]

Ok I am back!

After not being able to find anyone who is happy to swap parts as a process of elimination to find my issue, I have done the next best thing....

Yes I have bought another LS400, This one runs well and has done 163000 but still hits 60 in 8.8 seconds (so not much wrong with this engine).

It is also MOT'd and taxed and in the best colour BLACK. At £500 it was cheaper that replacing the sensors 1 by 1

Now I will swap parts in the hope I can get 2 running 400s

Will Post My Findings

[ROYT]

Brilliant!, that's dedication to the cause and two LS 400's one for each leg!

What's the total cars in stock now and when's the divorce....

[JellyBean]

Your perseverance will surely be rewarded. I applaud you for sticking with it and most of us will be most interested to see what the problem was.

[fuddymucker]

Brilliant!, that's dedication to the cause and two LS 400's one for each leg!

What's the total cars in stock now and when's the divorce....

I have 6 cars, 2 quads, 5 motorbikes and my pet hate is road tax

No sign of a divorce that I'm aware of......... but now you mention it....

[Nitmoi]

Nice to have the room for them!

[sir john]

i think its time for another membership status in addition to "new member" "advanced member" "guru" ect ect..

Hands up all those who have followed this thread and think that fuddymucker should be awarded "hero" status for sticking with something that would have had many of us chucking it in.

keep it up fuddymucker.. you give us all hope.

[JellyBean]

i think its time for another membership status in addition to "new member" "advanced member" "guru" ect ect..

Hands up all those who have followed this thread and think that fuddymucker should be awarded "hero" status for sticking with something that would have had many of us chucking it in.

keep it up fuddymucker.. you give us all hope.

Perhaps he could be awarded the Feroic Hucker gong?

[Malc]

Can you tell us the progress with resolving the problem ?

Malc

[fuddymucker]

Hello again all

Sorry I haven't updated for a while but I have been a tad busy..

After swapping all parts on the 1st LS400 for known good units on the 2nd LS400 I still had the same issue and this only puzzled me more.

Feeling that I had to give in sooner or later I left the car for a week to search for more logical reasons for my issue, during this week I found myself fitting a second hand multi point injection LPG conversion to the 2nd LS400 so I don't have to feel guilty using a V8 as my new best day to day drive.

So what about the 1st LS400.... well I have not found the fault...

as a car she is dead and I am breaking her body on eBay

However I will be transplanting her heart and soul to a new body, removing all her old tired faulty electrics and EGR rubbish then connecting up a state of art stand-alone waterproof ignition system and she will beat again but to a different tune.

Once running I will be installing it in to a all-terrain 4x4 rescue vehicle that will work in Somerset from the Mendip and Quantock hills to the Somerset levels and peat moors working along side the emergency services during the winter months accesing places they can’t get aid to due to floods, deep snow, mud ect..

Once complete I really will have the best of both worlds

A Lexus powered 4x4 recovery vehicle

And a Luxury economical LS400